April 16 2000 BRITAIN
Eyes rewired to ears in the brain could let the blind see
THE blind and brain-damaged could eventually benefit from
a radical new therapy after researchers announced they can
now rewire the mind, writes Jonathan Leake.
Studies have shown that connecting the eyes to the part of
the brain that controls hearing can restore vision. The work,
so far done only on animals, suggests that if doctors can
re-route nerve impulses away from injured areas they may
be able to restore lost functions.
The research, at the Massachusetts Institute of Technology
(MIT), involved surgically "rewiring" the brains of very young
mammals so that signals from the eye were sent to the
auditory cortex, which normally deals with hearing.
The animals soon learnt to see again, although not as well as
before, according to Mriganka Sur, professor and head of
brain and cognitive sciences at MIT.
He said the research could lead to treating brain disorders
that cause blindness.
"This is a profound discovery that addresses age-old
questions about whether the brain is genetically programmed
or shaped by the environment," he said. "It shows the ability
of the developing brain to adapt to environmental changes."
Previous research had shown that in people who were blind
from birth, the visual cortex in the brain assumed new
functions.
It is also well known that visual deprivation early in life alters
the way brain pathways develop. The MIT team reasoned
that this could mean the brain was flexible enough to adapt to
surgical rewiring.
Details of how they achieved the rewiring will be revealed in
a paper to be published in Nature, the science journal.
"Connections between cells are the key to brain function. By
altering the input to the tissue, the connections changed," said
Sur.
The researchers confirmed their results by training animals to
respond in certain ways to light stimuli.
After rewiring, the animals showed similar responses, even
though the impulses from their eyes were going to a different
part of the brain.
jonathan.leake@sunday-times.co.uk
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